
#ifndef __base_path_service_h__
#define __base_path_service_h__

#pragma once

#include "base/base_paths.h"

class FilePath;

// The path service is a global table mapping keys to file system paths.  It is
// OK to use this service from multiple threads.
//
class PathService
{
public:
    // Retrieves a path to a special directory or file and places it into the
    // string pointed to by 'path'. If you ask for a directory it is guaranteed
    // to NOT have a path separator at the end. For example, "c:\windows\temp"
    // Directories are also guaranteed to exist when this function succeeds.
    //
    // Returns true if the directory or file was successfully retrieved. On
    // failure, 'path' will not be changed.
    static bool Get(int key, FilePath* path);

    // Overrides the path to a special directory or file.  This cannot be used to
    // change the value of DIR_CURRENT, but that should be obvious.  Also, if the
    // path specifies a directory that does not exist, the directory will be
    // created by this method.  This method returns true if successful.
    //
    // If the given path is relative, then it will be resolved against
    // DIR_CURRENT.
    //
    // WARNING: Consumers of PathService::Get may expect paths to be constant
    // over the lifetime of the app, so this method should be used with caution.
    static bool Override(int key, const FilePath& path);

    // To extend the set of supported keys, you can register a path provider,
    // which is just a function mirroring PathService::Get.  The ProviderFunc
    // returns false if it cannot provide a non-empty path for the given key.
    // Otherwise, true is returned.
    //
    // WARNING: This function could be called on any thread from which the
    // PathService is used, so a the ProviderFunc MUST BE THREADSAFE.
    //
    typedef bool (*ProviderFunc)(int, FilePath*);

    // Call to register a path provider.  You must specify the range "[key_start,
    // key_end)" of supported path keys.
    static void RegisterProvider(ProviderFunc provider,
        int key_start,
        int key_end);
private:
    static bool GetFromCache(int key, FilePath* path);
    static bool GetFromOverrides(int key, FilePath* path);
    static void AddToCache(int key, const FilePath& path);
};

#endif //__base_path_service_h__